Re: Cosmic rays?? [7:71402] posted 06/26/2003
- Subject: Re: Cosmic rays?? [7:71402]
- From: "annlee" <aahines@xxxxxxxxx>
- Date: Thu, 26 Jun 2003 03:40:24 GMT
The only thing close to your story is the comment from Robert and Barbara
Thompson in _PC Hardware In A Nutshell, 2e_ where they comment that on a
device used as a server or any other PC that needs a large RAM, they always
use ECC memory (Error Checking and Correction) because (honest!) cosmic rays
One common cause of "flipped bit" memory errors is, believe it or not,
cosmic rays. The more memory you have installed, the more likely it is that
a random cosmic ray will impact one of the memory cells in a chip on your
system, causing the contents of that cell to flip from binary zero to a one
or vice versa. We don't pretend to understand this issue, but we've been
told by memory experts that for systems with 512MB of RAM, using ECC versus
non-parity memory is about an even trade-off in terms of extra cost and lost
performance versus the likelihood of memory errors. For systems with 768MB+,
we use ECC memory exclusively.
End quote (pp201-2).
However ... that could also be a Real Convenient Excuse. Do you have any
kind of other experience with the people who said this (like, are they
""Juan Carlos Perez"" wrote in message
> We have a Cisco VIP card plugged into a 7500 router. Every once in a
> the card just stops working and sometimes it gets stuck so hard that we
> have to reload the microcode. The last we did that, the router crashed and
> had to be reset (Ugly!). Well, it gets worse. After having to convince the
> guys at the local Cisco office to help us in this issue, they came to our
> facilities and began their analysis. To make a long story short, they told
> us that these problems were caused by cosmic rays! We almost fainted!
> Has anybody around here ever heard of this problem in this combo? Let me
> tell you this router is not installed in a spaceship or something like
> it4s just an ordinary datacenter.
> Any ideas about what the real problem might be?
> P. S. The router is using a recent version of IOS (newer than 12.1) and
> been patched as per the Cisco site.
> Thanks a lot for any advice on this issue.
Message Posted at:
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to abuse@xxxxxxxxxxxxxx